Researchers have created an underwater robot that swims in any direction using just one fin, inspired by the black ghost knife fish (Photo: Northwestern University)

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Article Summary

Ask anyone who keeps freshwater tropical fish to name the top five most exotic, bizarre fish available to hobbyists, and chances are the black ghost knife fish will be in there. Besides looking incredibly cool, these Amazon basin creatures have two rather unusual characteristics: they can sense all around themselves by generating a weak electrical field, and they can move in any direction, thanks to an undulating ribbon-like fin that runs along the length of their underside. In an effort to replicate that form of maneuverability for use in man-made submersibles, a team led by Northwestern University mechanical and biomedical engineer Dr. Malcolm MacIver has created the GhostBot – an underwater robot that moves via a knife fish-like fin.